1. Field of the Invention
This invention relates generally to video processing techniques, and relates more particularly to a system and method for flexibly blending multiple image planes in a video device.
2. Description of the Background Art
Implementing flexible and efficient methods for manipulating video data is a significant consideration of designers, manufacturers, and users of contemporary video devices. Video technology continues to evolve in response to a variety of converging factors such as marketplace competition and user demand for increased functionality. One aspect of the foregoing video evolution process has been a substantial increase in the relative complexity and system capabilities of various modern video devices.
For example, a digital video disc device may be utilized to view high-quality recorded audio-visual materials, such as motion pictures and other types of entertainment or educational programs. Similarly, a digital video broadcast system may provide high-quality programs for reproduction and viewing on a corresponding electronic playback system. The foregoing advanced digital video formats may provide additional functionality that was unavailable in earlier versions of electronic programming.
Many digital video encoding formats enable the inclusion of one or more subsidiary sets of displayable program information, in addition to the primary video program that typically includes video data for display to a system viewer. For example, one subsidiary set of video program information may include subtitles in a language other than that of the primary video program.
Simultaneously displaying multiple sets of video program information on a display monitor may present a variety of challenges to a system designer. In order to optimize the functionality of a video system that simultaneously displays multiple sets of program information, a video system may significantly benefit from a flexible and efficient design. For example, the ability to flexibly select, manipulate and blend a number of diverse video sources or image planes may provide significant benefit to users of video devices. Furthermore, the importance of system flexibility becomes accentuated when the number of video data sets or image planes increases.
Another concern associated with flexibly manipulating and blending multiple image planes of video information is the successful and accurate timing of each of the various image planes to achieve synchronicity when simultaneously displaying the image planes on a display monitor. Failure to correctly time each of the image planes may result in significant display offsets of the image planes in relation to other displayed image planes.
Therefore, for all the foregoing reasons, implementing an efficient method for flexibly blending multiple image planes of video data remains a significant consideration of designers, manufacturers, and users of contemporary video devices.
In accordance with the present invention, a system and method for flexibly blending multiple image planes in a video device is disclosed. In one embodiment, a timing controller initially accesses and references a master horizontal synchronization (hsync) signal. However, in alternate embodiments, various other signals may readily be utilized by timing controller as a reference. The timing controller then preferably receives a PF delay signal, an SP delay signal, and an OSD delay signal, however, in other embodiments, the timing controller may readily receive various other additional or different programmable delay signals.
Next, the timing controller preferably references the master hsync signal and responsively generates reshaped or adjusted hsync signals corresponding to the received delay signals. Specifically, the timing controller generates a PF hsync signal in response to a PF delay signal, an SP hsync signal in response to a SP delay signal, and an OSD hsync signal in response to an OSD delay signal. The timing controller then preferably provides the adjusted hsync signals to corresponding signal generation modules. More specifically, the timing controller provides the PF hsync signal to a postprocessing filter, the SP hsync signal to a subpicture decoder, and the OSD hsync signal to an OSD engine. In alternate embodiments, the adjusted synchronization signals may readily be provided to various other modules and devices, in accordance with the present invention.
Next, the postprocessing filter pre-synchronizes a PF video signal using the received PF hsync signal. Similarly, the subpicture decoder pre-synchronizes an SP video signal using the received SP hsync signal. Also, the OSD engine pre-synchronizes an OSD video signal using the received OSD hsync signal. The postprocessing filter then provides the pre-synchronized PF video signal to a blender device. The subpicture decoder similarly provides the pre-synchronized SP video signal to the blender device. Also, the OSD engine provides the pre-synchronized OSD video signal to the blender device.
In one embodiment of the present invention, the blender device responsively selects between the PF video signal and an external PDI signal to generate a selector A output signal. The blender device then blends the selector A output signal and the SP video signal in response to configurable blend factors to generate a mixer A output signal. Next, the blender device preferably selects between the mixer A output signal and the external PDI signal to generate a selector D output signal.
The blender device then preferably blends the selector D output signal and a mask video signal in response to configurable blend factors to generate a mixer B output signal. Next, the blender device preferably selects between the OSD video signal and the external PDI signal to generate a selector C output signal. Then, the blender device blends the mixer B output signal and the selector C output signal in response to configurable blend factors to generate a synchronized blender output signal, in accordance with the present invention. Finally, the blender device preferably selects between the PF video, the mixer A output signal, and the blender output signal to generate a pseudo output signal (PDO).
In alternate embodiments of the present invention, the foregoing blender device may readily perform processes and techniques that are different from, in addition to, or in varying order from those disclosed in conjunction with the foregoing embodiment. The present invention thus effectively implements a system and method for flexibly blending multiple image planes in a video device.